1. Field of the Invention
The present invention relates to a signal processing circuit that performs processing for an analog signal output from a head and a magnetic storage apparatus.
2. Description of the Related Art
For determining the quality of a head and a medium, a measurement of a read signal read out from the medium using the head is performed in the course of development and production of a magnetic storage apparatus such as an HDD (Hard Disk Drive). As one measurement method, there is known a technique of writing a solitary wave or a specific pattern on a medium and measuring a read signal through a measurement instrument. Recoding bit density (Du) obtained from the measurement is an important measurement item related to the quality and design of the head and medium.
Further, as one method for obtaining optimum setting parameters in signal equalization processing of an RDC (Read Channel Combo), there is known a method that requires a waveform of a solitary wave or the like actually measured. Concretely, the method writes a necessary pattern on a medium, reads the pattern on the medium, loads the waveform in a computer through a measurement instrument, and calculates optimum setting parameters in the computer.
However, in order to perform a measurement using the solitary wave, much man-power, man-hour, and an instrument for the measurement are required, which results in increase of cost. Further, it is difficult to calculate optimum setting parameters for each magnetic storage apparatus in its mass-production process. Further, in the case where an evaluation of a single LSI (Large Scale Integration) is performed without using the head and medium, an expensive facility, such as an arbitrary waveform generator, is required for generating an input signal to the LSI, thereby increasing cost.